The invention relates to a permanent splice joint between two high voltage cables, each having inner conductors covered by insulation which is in turn covered by a semi-conductive shield.
It is now common to provide such a splice joint wherein the shield of each cable is stripped from the insulation for a predetermined distance from the cable end and the insulation is stripped from the inner conductor a lesser predetermined distance from the cable end, to expose the inner conductor, the conductors of the two cables then being inserted into opposite ends of a compression connector which is thereupon crimped to the conductors, thus to join the same mechanically and electrically. The splice joint is completed by a known one piece housing comprising a tubular elastomeric sleeve having first and second coaxial end portions for receiving and gripping the insulation and shield of each of the first and second cables, and, between and joining the end portions a cylindrical central portion coaxial with the end portions for receiving and engaging the compression connector crimped to the inner conductors of the cables.
A splice joint utilizing the known housing is fashioned by preparing the cables as aforesaid, forcing the one piece known housing completely onto and over the shield of one of the cables, inserting the inner conductors of the cables into opposite ends of the compression connector, crimping the compression connector to the conductors and finally forcing the known housing in the direction opposite that in which it was forced to position it upon one of the cables, onto the other of said cables until one of the housing end portions grips the insulation and shield of the other one of said cables and the cylindrical central portion engages the compression connector.
The known housing is a unitary, composite structure. The outer surface of the housing from one end to the other is provided by an outer layer of semi-conductive rubber, the inner surface of the housing in the central portion is provided by an inner layer of semi-conductive rubber, which, in the completed splice joint engages the cable shields of both cables and the compression connector respectively for known electrical reasons and heat dissipation. The known housing further includes an intermediate layer of nonconductive rubber joined to the outer layer and the inner layer. In the completed splice joint, the inner surface of the intermediate layer of insulating material grips the insulation of both cables while the outer layer of semi-conductive rubber grips the insulation and the shield of both cables.
It is considered desirable that each size splice housing be able to be employed with a wide range of cable diameters. However, two competing factors have to be reconciled in order that the housing be functional. In order that adequate contact be made between the compression connector and the inner layer of semi-conductive rubber, the bore of the housing must be made small, but to permit ease of installation of the housing and to permit use of the housing with a wide range of cable diameters, the bore must be made large. Too small a bore and the frictional forces will prevent movement of the housing with respect to the cable. Too large a bore will ease installation of the housing over the cable shield but limit contact with the compression connector.
Various attempts have been made to ameliorate this disadvantage. Among these attempts are those of U.S. Pat. No. 3,673,311 issued on June 27, 1972 to Misare which eliminated the contact between the compression connector and the inner layer of semi-con of the housing and substituted a centrally located conductive filler which engaged to compression connector along a part of its outer periphery and U.S. Pat. No. 4,054,743 issued Oct. 18, 1977 to Mayer et al. which employs air pressure and an air cushion to reduce the gripping force of the housing until it is properly placed over the compression connector and in contact with the cables to be joined. One manufacturer uses a single size splice housing and varies the outside diameter of his compression connector for each cable size within that housing's range. A number of such housings and associated compression connectors are required. However, the frictional forces encountered during assembly are still great, and one needs a separate compression connector for each cable size and each housing size.
The present invention solves the problems as above set forth by providing a housing with sufficient inherent flexibility to make it feasible to slide the housing onto one of the cables to be joined and then to slide it to its final position, even where the cables are of the largest diameter intended for use with the inventive housing, an advantage which is attained while still obtaining sufficient electrical and mechanical engagement of the inner semi-conductive rubber layer with the compression connector.
Viewed from another prespective, a particular inventive housing can be used with a greater range of cable sizes than was possible with the known housing, thus reducing the number of different housings required. It is therefore an object of this invention to provide an improved splice housing.
It is an object of this invention to provide a splice housing which can be used with a wide range of cable sizes.
It is therefore an important object of the invention to provide an improved splice housing of substantially increased flexibility, thus making much easier the completion of splice joints by reducing assembly forces.
It is a further object to provide such an improved housing which does not sacrifice electrical or heat dissipating continuity.
It is an additional object to provide such an improved housing which is useful with cables of increased diameter ranges, with respect to the known housing. Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose and illustrate, by way of example, the principles of the invention and the best mode which has been contemplated for carrying it out.